/*==LICENSE==*

CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011 Cyan Worlds, Inc.

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.

Additional permissions under GNU GPL version 3 section 7

If you modify this Program, or any covered work, by linking or
combining it with any of RAD Game Tools Bink SDK, Autodesk 3ds Max SDK,
NVIDIA PhysX SDK, Microsoft DirectX SDK, OpenSSL library, Independent
JPEG Group JPEG library, Microsoft Windows Media SDK, or Apple QuickTime SDK
(or a modified version of those libraries),
containing parts covered by the terms of the Bink SDK EULA, 3ds Max EULA,
PhysX SDK EULA, DirectX SDK EULA, OpenSSL and SSLeay licenses, IJG
JPEG Library README, Windows Media SDK EULA, or QuickTime SDK EULA, the
licensors of this Program grant you additional
permission to convey the resulting work. Corresponding Source for a
non-source form of such a combination shall include the source code for
the parts of OpenSSL and IJG JPEG Library used as well as that of the covered
work.

You can contact Cyan Worlds, Inc. by email legal@cyan.com
 or by snail mail at:
      Cyan Worlds, Inc.
      14617 N Newport Hwy
      Mead, WA   99021

*==LICENSE==*/
#include "hsTypes.h"
#include "hsUtils.h"
#include "hsResMgr.h"
#include "../pnMessage/plRefMsg.h"
#include "../plMessage/plParticleUpdateMsg.h"
#include "plParticleGenerator.h"
#include "plParticleEmitter.h"
#include "plParticleSystem.h"
#include "plParticle.h"
#include "plParticleEffect.h"
#include "../CoreLib/hsColorRGBA.h"
#include "../plInterp/plController.h"
#include "../plSurface/hsGMaterial.h"
#include "../plSurface/plLayerInterface.h"
#include "plProfile.h"
#include "hsFastMath.h"

plProfile_CreateTimer("Update", "Particles", ParticleUpdate);
plProfile_CreateTimer("Generate", "Particles", ParticleGenerate);

plParticleEmitter::plParticleEmitter()
{
	fParticleCores = nil;
	fParticleExts = nil;
	fGenerator = nil;
	fLocalToWorld.Reset();
	fTimeToLive = 0;
}

void plParticleEmitter::Init(plParticleSystem *system, UInt32 maxParticles, UInt32 spanIndex, UInt32 miscFlags,
							 plParticleGenerator *gen /* = nil */)
{
	IClear();
	fSystem = system;
	plLayerInterface *layer = system->fTexture->GetLayer(0)->BottomOfStack();
	fMiscFlags = miscFlags | kNeedsUpdate;
	if( fMiscFlags & kOnReserve )
		fTimeToLive = -1.f; // Wait for someone to give us a spurt of life.
	if( layer->GetShadeFlags() & hsGMatState::kShadeEmissive )
	{
		fMiscFlags |= kMatIsEmissive;
		fColor = layer->GetAmbientColor();
	}
	else
	{
		fColor = layer->GetRuntimeColor();
	}
	fColor.a = layer->GetOpacity();
	fGenerator = gen;
	fMaxParticles = maxParticles;
	fSpanIndex = spanIndex;
	ISetupParticleMem();
}

void plParticleEmitter::Clone(plParticleEmitter* src, UInt32 spanIndex)
{
	Init(src->fSystem,
		src->fMaxParticles,
		spanIndex,
		src->fMiscFlags,
		src->fGenerator);

	fMiscFlags |= kBorrowedGenerator;
	fTimeToLive = -1.f;
}

void plParticleEmitter::OverrideLocalToWorld(const hsMatrix44& l2w)
{
	fLocalToWorld = l2w;
	fMiscFlags |= kOverrideLocalToWorld;
}

plParticleEmitter::~plParticleEmitter()
{
	IClear();
}

void plParticleEmitter::IClear()
{
	delete [] fParticleCores;
	fParticleCores = nil;
	delete [] fParticleExts;
	fParticleExts = nil;
	if( !(fMiscFlags & kBorrowedGenerator) )
		delete fGenerator;
	fGenerator = nil;
}

void plParticleEmitter::ISetupParticleMem()
{
	fNumValidParticles = 0;

	fParticleCores = TRACKED_NEW plParticleCore[fMaxParticles];
	fParticleExts = TRACKED_NEW plParticleExt[fMaxParticles];

	fTargetInfo.fPos = (UInt8 *)fParticleCores;
	fTargetInfo.fColor = (UInt8 *)fParticleCores + sizeof(hsPoint3);
	fTargetInfo.fPosStride = fTargetInfo.fColorStride = sizeof(plParticleCore);

	fTargetInfo.fVelocity = (UInt8 *)fParticleExts;
	fTargetInfo.fInvMass = fTargetInfo.fVelocity + sizeof(hsVector3);
	fTargetInfo.fAcceleration = fTargetInfo.fInvMass + sizeof(hsScalar);
	fTargetInfo.fMiscFlags = (UInt8 *)&(fParticleExts[0].fMiscFlags);	
	fTargetInfo.fRadsPerSec = (UInt8 *)&(fParticleExts[0].fRadsPerSec);
	fTargetInfo.fVelocityStride 
		= fTargetInfo.fInvMassStride 
		= fTargetInfo.fAccelerationStride 
		= fTargetInfo.fRadsPerSecStride
		= fTargetInfo.fMiscFlagsStride 
		= sizeof(plParticleExt);
}

UInt32 plParticleEmitter::GetNumTiles() const
{ 
	return fSystem->GetNumTiles(); 
}

const hsMatrix44 &plParticleEmitter::GetLocalToWorld() const
{ 
	return fMiscFlags & kOverrideLocalToWorld ? fLocalToWorld : fSystem->GetLocalToWorld(); 
}

void plParticleEmitter::AddParticle(hsPoint3 &pos, hsVector3 &velocity, UInt32 tileIndex, 
								    hsScalar hSize, hsScalar vSize, hsScalar scale, hsScalar invMass, hsScalar life,
									hsPoint3 &orientation, UInt32 miscFlags, hsScalar radsPerSec)
{
	plParticleCore *core;
	plParticleExt *ext;
	UInt32 currParticle;

	if (fNumValidParticles == fMaxParticles)
		return; // No more room... you lose!
	else
		currParticle = fNumValidParticles++;

	core = &fParticleCores[currParticle];	
	core->fPos = pos;
	core->fOrientation = orientation;
	core->fColor = CreateHexColor(fColor);
	core->fHSize = hSize * scale;
	core->fVSize = vSize * scale;

	// even if the kNormalUp flag isn't there, we should initialize it to something sane.
	//if (core->fMiscFlags & kNormalUp != 0)
		core->fNormal.Set(0, 0, 1);

	hsScalar xOff = (tileIndex % fSystem->fXTiles) / (float)fSystem->fXTiles;
	hsScalar yOff = (tileIndex / fSystem->fXTiles) / (float)fSystem->fYTiles;

	core->fUVCoords[0].fX = xOff;
	core->fUVCoords[0].fY = yOff + 1.0f / fSystem->fYTiles;
	core->fUVCoords[0].fZ = 1.0f;
	core->fUVCoords[1].fX = xOff + 1.0f / fSystem->fXTiles;
	core->fUVCoords[1].fY = yOff + 1.0f / fSystem->fYTiles;
	core->fUVCoords[1].fZ = 1.0f;
	core->fUVCoords[2].fX = xOff + 1.0f / fSystem->fXTiles;
	core->fUVCoords[2].fY = yOff;
	core->fUVCoords[2].fZ = 1.0f;
	core->fUVCoords[3].fX = xOff;
	core->fUVCoords[3].fY = yOff;
	core->fUVCoords[3].fZ = 1.0f;

	ext = &fParticleExts[currParticle];
	ext->fVelocity = velocity;
	ext->fInvMass = invMass;
	ext->fLife = ext->fStartLife = life;
	ext->fMiscFlags = miscFlags; // Is this ever NOT zero?
	if (life <= 0) 
		ext->fMiscFlags |= plParticleExt::kImmortal;

	ext->fRadsPerSec = radsPerSec;
	ext->fAcceleration.Set(0, 0, 0);
	ext->fScale = scale;
}

void plParticleEmitter::WipeExistingParticles()
{ 
	fNumValidParticles = 0;  // That was easy.
}

// This method is called from a network received message. Don't trust the args without checking.
void plParticleEmitter::KillParticles(hsScalar num, hsScalar timeToDie, UInt8 flags)
{
	if (flags & plParticleKillMsg::kParticleKillPercentage)
	{
		if (num < 0)
			num = 0;
		if (num > 1)
			num = 1;

		num *= fNumValidParticles;
	}
	else
	{
		if (num < 0)
			num = 0;
	}

	if (timeToDie < 0)
		timeToDie = 0;

	int i;
	for (i = 0; i < fNumValidParticles && num > 0; i++)
	{
		if ((flags & plParticleKillMsg::kParticleKillImmortalOnly) && !(fParticleExts[i].fMiscFlags & plParticleExt::kImmortal))
			continue;

		fParticleExts[i].fLife = fParticleExts[i].fStartLife = timeToDie;
		fParticleExts[i].fMiscFlags &= ~plParticleExt::kImmortal;
		num--;
	}
}

void plParticleEmitter::UpdateGenerator(UInt32 paramID, hsScalar paramValue)
{
	if (fGenerator != nil)
		fGenerator->UpdateParam(paramID, paramValue);
}

UInt16 plParticleEmitter::StealParticlesFrom(plParticleEmitter *victim, UInt16 num)
{
	UInt16 spaceAvail = (UInt16)(fMaxParticles - fNumValidParticles);
	UInt16 numToCopy = (UInt16)(hsMinimum(num, (victim ? victim->fNumValidParticles : 0)));
	if (spaceAvail < numToCopy)
		numToCopy = spaceAvail;

	if (numToCopy > 0)
	{
		// copy them over
		memcpy(&(fParticleCores[fNumValidParticles]), &(victim->fParticleCores[victim->fNumValidParticles - numToCopy]), numToCopy * sizeof(plParticleCore));
		memcpy(&(fParticleExts[fNumValidParticles]), &(victim->fParticleExts[victim->fNumValidParticles- numToCopy]), numToCopy * sizeof(plParticleExt));

		fNumValidParticles += numToCopy;
		victim->fNumValidParticles -= numToCopy;
	}

	return numToCopy;
}

void plParticleEmitter::TranslateAllParticles(hsPoint3 &amount)
{
	int i;
	for (i = 0; i < fNumValidParticles; i++)
		fParticleCores[i].fPos += amount;
}

hsBool plParticleEmitter::IUpdate(hsScalar delta)
{
	if (fMiscFlags & kNeedsUpdate)
	{
		plProfile_BeginTiming(ParticleUpdate);

		IUpdateParticles(delta);
		IUpdateBoundsAndNormals(delta);

		plProfile_EndTiming(ParticleUpdate);
	}

	if (fGenerator == nil && fNumValidParticles <= 0)
		return false; // no generator, no particles, let the system decide if this emitter is done
	else
		return true;
}

void plParticleEmitter::IUpdateParticles(hsScalar delta)
{

	int i, j;

	// Have to remove particles before adding new ones, or we can run out of room.
	for (i = 0; i < fNumValidParticles; i++)
	{
		fParticleExts[i].fLife -= delta;
		if (fParticleExts[i].fLife <= 0 && !(fParticleExts[i].fMiscFlags & plParticleExt::kImmortal))
		{
			IRemoveParticle(i);
			i--; // so that we hit this index again on the next iteration
			continue;
		}
	}

	fTargetInfo.fFirstNewParticle = fNumValidParticles;
	
	if ((fGenerator != nil) && (fTimeToLive >= 0))
	{
		plProfile_BeginLap(ParticleGenerate, fSystem->GetKeyName());
		if (!fGenerator->AddAutoParticles(this, delta))
		{
			delete fGenerator;
			fGenerator = nil;
		}
		if( (fTimeToLive > 0) && ((fTimeToLive -= delta) <= 0) )
			fTimeToLive = -1.f;
		plProfile_EndLap(ParticleGenerate, fSystem->GetKeyName());
	}

	fTargetInfo.fContext = fSystem->fContext;
	fTargetInfo.fNumValidParticles = fNumValidParticles;
	const hsVector3 up(0, 0, 1.0f);
	hsVector3 currDirection;
	hsPoint3 *currPos;
	hsVector3 *currVelocity;
	hsVector3 *currAccel;
	hsPoint3 color(fColor.r, fColor.g, fColor.b);
	hsScalar alpha = fColor.a;
	plController *colorCtl;

	// Allow effects a chance to cache any upfront calculations
	// that will apply to all particles.
	for (j = 0; j < fSystem->fForces.GetCount(); j++)
	{
		fSystem->fForces[j]->PrepareEffect(fTargetInfo);
	}
	for (j = 0; j < fSystem->fEffects.GetCount(); j++)
	{
		fSystem->fEffects[j]->PrepareEffect(fTargetInfo);
	}
	for (j = 0; j < fSystem->fConstraints.GetCount(); j++) 
	{
		fSystem->fConstraints[j]->PrepareEffect(fTargetInfo);
	}

	for (i = 0; i < fNumValidParticles; i++)
	{
		if (!( fParticleExts[i].fMiscFlags & plParticleExt::kImmortal ))
		{			
			hsScalar percent = (1.0f - fParticleExts[i].fLife / fParticleExts[i].fStartLife);
			colorCtl = (fMiscFlags & kMatIsEmissive ? fSystem->fAmbientCtl : fSystem->fDiffuseCtl);
			if (colorCtl != nil)
				colorCtl->Interp(colorCtl->GetLength() * percent, &color);

			if (fSystem->fOpacityCtl != nil)
			{
				fSystem->fOpacityCtl->Interp(fSystem->fOpacityCtl->GetLength() * percent, &alpha);
				alpha /= 100.0f;
				if (alpha < 0)
					alpha = 0;
				else if (alpha > 1.f)
					alpha = 1.f;
			}

			if (fSystem->fWidthCtl != nil)
			{
				fSystem->fWidthCtl->Interp(fSystem->fWidthCtl->GetLength() * percent,
										   &fParticleCores[i].fHSize);
				fParticleCores[i].fHSize *= fParticleExts[i].fScale;
			}
			if (fSystem->fHeightCtl != nil)
			{
				fSystem->fHeightCtl->Interp(fSystem->fHeightCtl->GetLength() * percent,
										    &fParticleCores[i].fVSize);
				fParticleCores[i].fVSize *= fParticleExts[i].fScale;
			}

			fParticleCores[i].fColor = CreateHexColor(color.fX, color.fY, color.fZ, alpha);						
		}

		for (j = 0; j < fSystem->fForces.GetCount(); j++)
		{
			fSystem->fForces[j]->ApplyEffect(fTargetInfo, i);
		}
		
		currPos = (hsPoint3 *)(fTargetInfo.fPos + i * fTargetInfo.fPosStride);
		currVelocity = (hsVector3 *)(fTargetInfo.fVelocity + i * fTargetInfo.fVelocityStride);
		//currAccel = (hsVector3 *)(fTargetInfo.fAcceleration + i * fTargetInfo.fAccelerationStride);
		currAccel = &fSystem->fAccel; // Nothing accellerates on a per-particle basis (yet)

		*currPos += *currVelocity * delta;

		// This is the only orientation option (so far) that requires an update here
		if (fMiscFlags & (kOrientationVelocityBased | kOrientationVelocityStretch | kOrientationVelocityFlow))
			fParticleCores[i].fOrientation.Set(&(*currVelocity * delta)); // mf - want the orientation to be a delposition
		else if( fParticleExts[i].fRadsPerSec != 0 )
		{
			hsScalar sinX, cosX;
			hsFastMath::SinCos(fParticleExts[i].fLife * fParticleExts[i].fRadsPerSec * 2.f * hsScalarPI, sinX, cosX);
			fParticleCores[i].fOrientation.Set(sinX, -cosX, 0);
		}

		// Viscous force F(t) = -k V(t)
		// Integral S from t0 to t1 of F(t) is
		// = S(-kV(t))[t1..t0]
		// = -k(P(t1) - P(t0))
		// = -k*(currVelocity * delta)
		// or
		// V = V + -k*(V * delta)
		// V *= (1 + -k * delta)
		// Giving the change in velocity.
		hsScalar drag = 1.f + fSystem->fDrag * delta;
		// Clamp it at 0. Drag should never cause a reversal in velocity direction.
		if( drag < 0.f )
			drag = 0.f;
		*currVelocity *= drag;

		*currVelocity += *currAccel * delta;

		for (j = 0; j < fSystem->fEffects.GetCount(); j++)
		{
			fSystem->fEffects[j]->ApplyEffect(fTargetInfo, i);
		}

		// We may need to do more than one iteration through the constraints. It's a trade-off
		// between accurracy and speed (what's new?) but I'm going to go with just one
		// for now until we decide things don't "look right"
		for (j = 0; j < fSystem->fConstraints.GetCount(); j++) 
		{
			if( fSystem->fConstraints[j]->ApplyEffect(fTargetInfo, i) )
			{
				IRemoveParticle(i);
				i--; // so that we hit this index again on the next iteration
				break; 
				// break will break us out of loop over constraints,
				// and since we're last, we move onto next particle.
			}
		}
	}

	// Notify the effects that they are done for now.
	for (j = 0; j < fSystem->fForces.GetCount(); j++)
	{
		fSystem->fForces[j]->EndEffect(fTargetInfo);
	}
	for (j = 0; j < fSystem->fEffects.GetCount(); j++)
	{
		fSystem->fEffects[j]->EndEffect(fTargetInfo);
	}
	for (j = 0; j < fSystem->fConstraints.GetCount(); j++) 
	{
		fSystem->fConstraints[j]->EndEffect(fTargetInfo);
	}
}

plProfile_CreateTimer("Bound", "Particles", ParticleBound);
plProfile_CreateTimer("Normal", "Particles", ParticleNormal);

void plParticleEmitter::IUpdateBoundsAndNormals(hsScalar delta)
{
	plProfile_BeginTiming(ParticleBound);
	fBoundBox.MakeEmpty();
	int i;
	for (i = 0; i < fNumValidParticles; i++)
		fBoundBox.Union(&fParticleCores[i].fPos);
	
	hsPoint3 center;
	if (fNumValidParticles > 0)
		center = fBoundBox.GetCenter();
	plProfile_EndTiming(ParticleBound);

	plProfile_BeginTiming(ParticleNormal);
	hsVector3 normal;
	if (fMiscFlags & kNormalVelUpVel)
	{
		for (i = fNumValidParticles - 1; i >=0; i--) 
		{
			//currDirection.Set(&fParticleCores[i].fPos, &fParticleExts[i].fOldPos);
			//normal = (currDirection % up % currDirection);
			normal.Set(-fParticleExts[i].fVelocity.fX * fParticleExts[i].fVelocity.fZ,
					   -fParticleExts[i].fVelocity.fY * fParticleExts[i].fVelocity.fZ,
					   (fParticleExts[i].fVelocity.fX * fParticleExts[i].fVelocity.fX + 
					    fParticleExts[i].fVelocity.fY * fParticleExts[i].fVelocity.fY));
			if (!normal.IsEmpty()) // zero length check
			{
				normal.Normalize();
				fParticleCores[i].fNormal = normal;
			}
		}
	}
	else if (fMiscFlags & kNormalFromCenter)
	{
		for (i = fNumValidParticles - 1; i >=0; i--) 
		{
			normal.Set(&fParticleCores[i].fPos, &center);
			if (!normal.IsEmpty()) // zero length check
			{
				normal.Normalize();
				fParticleCores[i].fNormal = normal;
			}
		}
	}
	// otherwise we just keep the last normal.
	plProfile_EndTiming(ParticleNormal);
}

void plParticleEmitter::IRemoveParticle(UInt32 index)
{
	hsAssert(index < fNumValidParticles, "Trying to remove an invalid particle");

	fNumValidParticles--;
	if (fNumValidParticles <= 0)
	{
		fNumValidParticles = 0;
		return;
	}

	fParticleCores[index] = fParticleCores[fNumValidParticles];
	fParticleExts[index] = fParticleExts[fNumValidParticles];
}

// Reading and writing doesn't transfer individual particle info. We assume those are expendable.
// Only the configuration info necessary to began spawning particles again is saved.
// The particle system that owns this emitter is responsible for setting the pointer back to itself
void plParticleEmitter::Read(hsStream *s, hsResMgr *mgr)
{
	plCreatable::Read(s, mgr);

	fGenerator = plParticleGenerator::ConvertNoRef(mgr->ReadCreatable(s));
	fSpanIndex = s->ReadSwap32();
	fMaxParticles = s->ReadSwap32();
	fMiscFlags = s->ReadSwap32();
	fColor.Read(s);

	if( fMiscFlags & kOnReserve )
		fTimeToLive = -1.f; // Wait for someone to give us a spurt of life.

	ISetupParticleMem();
}

void plParticleEmitter::Write(hsStream *s, hsResMgr *mgr)
{
	plCreatable::Write(s, mgr);

	mgr->WriteCreatable(s, fGenerator);
	s->WriteSwap32(fSpanIndex);
	s->WriteSwap32(fMaxParticles);
	s->WriteSwap32(fMiscFlags);
	fColor.Write(s);
}

UInt32 plParticleEmitter::CreateHexColor(const hsColorRGBA &color)
{
	return CreateHexColor(color.r, color.g, color.b, color.a);
}

UInt32 plParticleEmitter::CreateHexColor(const hsScalar r, const hsScalar g, const hsScalar b, const hsScalar a)
{
	UInt32		ru, gu, bu, au;

	au = (UInt32)(a * 255.0f);
	ru = (UInt32)(r * 255.0f);
	gu = (UInt32)(g * 255.0f);
	bu = (UInt32)(b * 255.0f);
	return ( au << 24 ) | ( ru << 16 ) | ( gu << 8 ) | ( bu );
}